The processes of thermal biomass processing, using pyrolysis and gasification are well known. The technical inconvenience met in these processes is the large amount of water in the biomass, which necessitates evaporating the excess water. Heating of biomass is performed using conventional energy sources, such as gas or oil burners, electric heating systems, and the process of heating occurs as a result of heat conduction through the walls of a reactor.
There is known a method of hydrothermal liquefaction of biomass using indirect heating of liquefied material. This process requires high pressure in the reactor chamber and the biomass has to be heated to a high temperature. This requires application of special technical means for the process chambers. The basic technical inconvenience of the existing solutions is the difficulty of heating the biomass in its whole volume to the required temperature, as the biomass is heated only via the walls of the reactor. Excessively high temperatures of the reactor chamber walls may produce water vapour and result in local gasification and reduction of the effectiveness of the biomass liquefaction. Excessively low temperatures of biomass inside the reactor chamber, which does not adhere to the reactor's walls, may influence the reduction of liquefying efficiency and increase of volume of biocoal.
Among the existing technical solutions for the systems for hydrotechnical liquefaction of biomass there is known the HTU (Hydrothermal Upgrading) technology developed by the Stell company. In this technology, biomass undergoes liquefaction in about 5-20 minutes and about 45% of biofuel is obtained in relation to the weight of the batch material. The relatively long time of biomass liquefaction results from the technical difficulty of obtaining the required temperature in the whole volume of liquefied biomass.
Another example of known technical solutions is the NOR (New Oil Resources) technology, in which a two-stage process is performed: the first stage involves decomposition of biomass into simpler organic compounds under high temperature and pressure, whilst the second stage utilises recombination processes to generate fuel fractions.
All of the existing solutions involve supply of heat from the heated walls of the reactor to the biomass being mixed.